Multi-bond Network Hydrogels with Robust Mechanical and Self-healable Properties

• Published in: Chinese journal of polymer science 2017-10, Vol.35 (10), p.1253-1267
• Main Authors: Liu, Xiao-ying, Zhong, Ming, Shi, Fu-kuan, Xu, Hao, Xie, Xu-ming
• Format: Article
• Language: English
• Subjects: Acrylic acid; Bond energy; Characterization and Evaluation of Materials; Chemical bonds; Chemistry; Chemistry and Materials Science; Condensed Matter Physics; Crosslinking; Dissipation; Elongation; Energy distribution; Ferric ions; Gels; Hydrogels; Hydrogen bonds; Industrial Chemistry/Chemical Engineering; Links; Mechanical properties; Polymer Sciences; Self healing materials; 愈合; 拉伸性能; 机械性能; 物理水凝胶; 离子交联; 网络; 聚合物链; 自愈性
• ISSN: 0256-7679; 1439-6203
• DOI: 10.1007/s10118-017-1971-0

Multi-bond network（MBN） which contains a single network with hierarchical cross-links is a suggested way to fabricate robust hydrogels. In order to reveal the roles of different cross-links with hierarchical bond energy in the MBN, here we fabricate poly（acrylic acid） physical hydrogels with dual bond network composed of ionic cross-links between carboxylFe3＋ interactions and hydrogen bonds, and compare these dually cross-linked hydrogels with singly and ternarily cross-linked hydrogels. Simple models are employed to predict the tensile property, and the results confirm that the multi-bond network with hierarchical distribution in the bond energy of cross-links endows hydrogel with effective energy-dissipating mechanism. Moreover, the dually cross-linked MBN gels exhibit excellent mechanical properties（tensile strength up to 500 k Pa, elongation at break ~ 2400%） and complete self-healing after being kept at 50 °C for 48 h. The factors on promoting self-healing are deeply explored and the dynamic multi-bonds are regarded to trigger the self-healing along with the mutual diffusion of long polymer chains and ferric ions.